Refrigeration apparatus



Dec. 24, 1940. H. D. SHAW REFRIGERATION APPARATUS Filed July 15, 1939INVENTOR HAROLD D. SHAW.

WITN ESS ES:

BY Z

ATTOR EY Patented Dec. 24, 1940 UNITED STATES PATENT OFFICE 2,225,932REFRIGERATION APPARATUS Pennsylvania Application my 15, 1939, Serial No.284,635

Claims.

My invention relates to refrigeration apparatus and particularly to adefrosting signal for refrigeration apparatus.

In refrigeration apparatus, particularly of the 5 domestic type, it iswell known that frost builds up on the evaporator or cooling element ofthe refrigerator and that periodic defrosting is necessary. While manyautomatic defrosting schemes have been suggested, it is stilladvantageous for reasons of cleanliness and cost of manufacture tomanually defrost the cooling element. However, the operator of therefrigerator in many instances neglects to defrost the cooling elementand. if frost builds up to a suificient l5 thickness, it deleteriouslyaffects the operation and efficiency of the refrigerating mechanism.

It is, therefore, an object of my invention to provide a visual signalwhich indicates when the cooling element of the refrigerator should bede- 20 frosted.

It is another object of my invention to provide a visual defrostingsignal which utilizes the same light source that is used forilluminating the food storage compartment of the refrigerator.

25 It is another object of my invention to provide for changes either inquality or quantity of light which is transmitted from a light source toindicate when defrosting is necessary.

It is a further object of my invention to pro- 30 vide a novel lighttransmitting means for indicating when defrosting is necessary.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in connection with 35the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a front view of a portion of a domestic refrigeratorillustrating one embodiment of my invention;

40 Fig. 2 is a sectional view of the refrigerator shown in Fig. 1 takenon line 11-11 thereof;

Fig. 3 is a fragmentary detailed View of a portion of a refrigeratorillustrating a second embodiment of my invention; and,

-13 Fig. 4 is a fragmentary detailed view of a portion of a refrigeratorillustrating a third embodiment of my invention.

Referring specifically to Figs. 1 and 2 for a detailed description of myinvention, numeral 50 generally indicates a refrigerator cabinetincluding heat insulated walls I! which define a food I storagecompartment l3. A cooling element It, preferably of the evaporativetype, abstracts heat from the food storage compartment l3, refriger- 55ant belhg circulated therethrough by a conventional refrigerating system(not shown). A shelf |5 is positioned in the food storage compartmentand supports a receptacle It for storing meats and the like directlybelow the evaporator It.

A door I! closes the food storage compartment 5 l3 and, when in itsclosed position, forces a plunger l8 of a door-operated switch I!inwardly, thus breaking an electrical circuit from line L1 In tocontacts 2| and to an incandescent lamp 22. When the door I! is opened,the plunger I8 is 10 forced outwardly by a spring 23 -so that thecontacts 2| are closed and the incandescent lamp 22 is energized toilluminate the interior of the food storage compartment |3.

In accordance with the first embodiment of the invention shown in Figs.1 and 2, heat-insulating blocks 25 and 25 are attached to the bottom ofthe evaporator I4 by screws 21, the block 25 being positioned near thefront of the evaporator and the block 26 near the rear thereof. Thefront block is provided with an ornamental front surface 28 and with acut-out portion 29 in communication with the compartment l3 andpreferably adjacent a corrugation 3| of, the evaporator II. t

As best shown in Fig. 2, a light-transmitting device 30 comprises tworods 32 and 33. The rods 32 and 33 are supported by the blocks 25 and 26and are spaced apart at 34 in the cut-out portion, 29 of the block 25.One end 35 of the rod "30 extends outwardly of the block 25 and an end36 of the rod 33 is bent downwardly at 31 and extends in close proximityto the incandescent lamp 22. The rods are preferably formed of a methylmethacylate resin known by the trade-marked 35 name Lucite, althoughthey may be formed of fused quartz, glass or any fairly efficientlighttransmitting material. The trade-marked material Lucite isespecially applicable because it is an efficient light transmitter, maybe made of 40 different colors, and transmits light around bends withvery little loss in intensity.

In operation, when the cooling element It is not in need of defrostingand the door H is opened, the incandescent lamp 22 is energized andlight therefrom not only illuminates the food storage compartment l3,but is also transmitted along rod 33, across the space 34 between therods and through rod 32 to the visible end 35 thereof. The end 35therefore glows and shows that the cooling element It is not in need ofdefrosting. When frost builds up on the cooling element H to apredetermined degree, for example, V}. of an inch, it also builds up oncorrugation 3| and closes the space 34 between rods 32 and 33.

2 2,225,932 I 7 When this occurs. light is no longer transmitted ingnormal operation, a source of light andtothefrontrodflandthecxposedendflthereof ceases to glow, thereby givinga visual indication that the cooling clement ll should be defrosted.Eitherorbothrods flandllmaybe made of colored material so that coloredlight is visible at the expmed end 88 of the rod 32.

In the second embodiment of my invention:

shown in Fig. 3, the rods "and 33 are arranged 10 as shown in Figs. 1and 2 but a third continuous rod II is also supp rted by the blocks fland I8.-

Rod 38 has one end It adjacent the incandescent lamp 2! and the otherexposed end ll thereof positioned directly below end I! of rod 32. Theadvantage of such an arrangement is that the end ll of rod 38 willalways glow when door I! is open whether defrosting is necessary or not,thus calling the operator's attention to the defrost indicator. Ifdesired, end it of rod 32 may glow with light of one color, for example,green, while end I! of rod a may glow with another color, for example,red.

The third embodiment of my invention disclosed in Fig. 4 of the drawingis constructed exactly the same as that shown in Fig. 3 except that anexposed colorless focusing device 4! collects light from rods 32 and 38so that, if rods 32 and ll are of diiierent colors, as frost builds upin the space ,between rods 32 and", the color .3 of the light willchange in the focusing device 42, this indicating the need fordefrosting. This embodiment also has the advantage that the device 42always glows when the door I1 is open with some color of light, thuscalling the operator's attention to the defrost indicator.

From the foregoing, it will be apparent that I have provided an improveddefrosting indicator for refrigerators in which the source of lightwhich illuminates the interior of the food storage 40 compartment isutilized. I furthermore provide a defrosting indicator which isattractive in appearance and inexpensive to install in a refrigerator.

While I have shown my invention in several forms, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and modifications without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are specifically set forth in the appendedclaims.

What I claim is: v

1. In refrigeration apparatus, the combination of a cooling elementwhich collects frost during normal operation, a source of light andmeans for transmitting light from the source to a location where it isreadily visible and for varying the light transmitted as a signal whendefrosting is necessary, said means comprising a light- Q transmittingmaterial having at least a part thereof disposed adjacent to the coolingelement and having a break therein so positioned-.that

whenthe' frost builds up on the cooling element to a predetermineddegree it enters the break and varies the light transmitted by saidlighttransmitting material.

2. In refrigeration apparatus, the combination of a cooling elementwhich collects frost durmeans for transmitting light from the-source toa location where it is readily visible and for varying the lighttransmitted as a signal when defrosting is necessary, said meanscomprising a plurality of light-transmitting devices, at least one'ofwhich is disposedadiacent the cooling element with a break therein soarranged that .whcn the frost on the cooling element builds up to apredetermined thickness it enters the break and varies the lighttransmitted by one of the devices.

8. In refrigeration apparatus, the combination of a cooling elementwhich collects frost during normal operation, a source of light, meansfor transmitting light from the source to a location where it is readilyvisible'and for varying the light transmitted as a signal whendefrosting is necessary, said means comprising a plurality oflight-transmitting devices, at least one of which is dispwed adjacent tothe cooling element with a break therein so arranged that when the froston the cooling element builds up to a predetermined thickness, it entersthe break and 'varies the light transmitted by one of the devices, andmeans for focusing the light from both of said devices at a singlepoint.

4. In refrigeration apparatus, the combination of a cooling elementwhich collects frost during normal operation, a source of light, meansfor transmitting light from the source to a location where it'is readilyvisible and for varying the light transmitted as a signal whendefrosting is necessary, said means comprising a plurality of.light-transmitting devices, at least one of which is disposed adjacentto the cooling element with a space therein so arranged that when thefrost on the cooling element builds up to a predetermined thickness, itenters the space and varies the light transmitted by one of the devices,and means for focusing the light for both of, said devices at a singlepoint, said devices transmitting different colored light so that thecolor changes at said point when the frost builds up to a predeterminedthickness.

5. In refrigeration apparatus, the combination of a refrigerator cabinetembodying a food storage compartment and having an access openingthereto, a door for closing the access opening, a

cooling element disposed in the food storage com- I partment whichcollects frost during normal operation, a source of light, means fortransmitting light from the source to a location where I it is readilyvisible and for varying the light transmitted as a signal whendefrosting is necessary,

